As an important tracer of star formations and chemical enrichment in galaxies, HII regions play a fundamental role in our understanding of galaxy evolution. To infer the physical conditions of HII regions in galaxies, many diagnostic methods based on the emission-line spectra of the ionized gas have been proposed. Meanwhile, people have constructed theoretical models to describe the ionization ...
As fuel feeding supermassive black hole and star formation, cold molecular gas is the key to many fundamental processes in galaxy evolution. In the last decade and especially with the advent of Atacama Large Millimeter/submillimeter Array (ALMA), it has become feasible to spatially resolve giant molecular clouds (GMCs) in a large number and a wide variety of galaxies. Here, I summarise my work ...
In this talk, I will discuss two ongoing spectroscopic programs to study the stellar streams in our Milky Way and highlight a few latest scientific results from these two programs. The Southern Stellar Stream Spectroscopic Survey (S5), started in 2018, is the first systematic program pursuing a complete census of known streams in the Southern Hemisphere. The science results from S5 include a ho...
The 3D structure and extinction law are studied for the Taurus, Orion, Perseus and California molecular clouds (MCs) based on the LAMOST and APOGEE spectroscopy. Extinctions are calculated from color excess derived from the Blue Edge methods. In combination with the distance from the Gaia, a 3D extinction map and the structure of these MCs can be retrieved and the clouds that overlap in the sk...
Evolutions of stars, black hole accretion as well as interactions between stars and black holes play an important role in various astrophysical systems, such as supernova, X-ray binaries, AGNs as well as various transient phenomena. I will discuss some long standing issues related to massive star and black hole systems. Then I will describe some examples on how we can make progress on some of ...